PA-13-058 (Pain in Aging): The 2011 Institute of Medicine report entitled Relieving Pain in America noted that 62% of nursing home (NH) residents experience pain. Despite a decade of evidence, the introduction of quality indicators and the initiation of quality improvement programs, pain management in nursing homes is sub-optimal. Pain is seldom an isolated symptom and is often associated with/accompanied by other symptoms in common clusters. The proposed work seeks to use a novel analytic approach to characterize pain symptom clusters in NH residents using a contemporaneous dataset. We propose merging elements of the following existing databases: the Minimum Data Set (MDS), Medicare eligibility and claims data (Part A, B & D), and the Certification and Survey Provider Enhanced Reporting (CASPER) system. The specific aims are to: 1) Identify the most common and burdensome pain symptom clusters among nursing home residents and describe correlates of pain symptom clusters; 2) Describe medication use by pain symptom clusters; 3) Evaluate trajectories of pain symptom clusters and corresponding medication use; and 4) Quantify the extent to which medications are associated with outcomes such as improvements in pain trajectories and adverse events (falls, fractures, constipation, and overall hospitalizations and hospitalizations for specific causes). State of the art statistical techniques including latent clas modeling and marginal structural models will be used. All analyses will be conducted by underlying diagnosis (e.g., those with and without a cancer diagnosis), sociodemographic (age, gender and race/ethnicity), and cognitive and functional impairment. Despite administrative initiatives including the inclusion of pain as a quality indicator and public reporting of measures and directives in surveyors' interpretive guidance documents regarding polypharmacy and pain, untreated, potentially undertreated and inappropriately treated pain remain common in the nursing home setting. No studies have attempted to characterize pain symptom clusters in nursing homes and to longitudinally explore the changes in pain, pharmacological pain treatments, and outcomes in a contemporaneous national dataset of nursing home residents. This is a novel area of exploration that will provide needed information to form the basis of strategies to improve pain management in NHs.